Accurate bandgaps of photovoltaic kesterites from first-principles DFT+U

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Hauptverfasser: Burgess, Andrew C., MacEnulty, Lórien, D'Arcy, Ethan, Gavin, David, O'Regan, David D.
Format: Preprint
Veröffentlicht: 2025
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author Burgess, Andrew C.
MacEnulty, Lórien
D'Arcy, Ethan
Gavin, David
O'Regan, David D.
author_facet Burgess, Andrew C.
MacEnulty, Lórien
D'Arcy, Ethan
Gavin, David
O'Regan, David D.
contents Streamlined prediction of the electronic properties of photoactive materials warrants a Density Functional Theory (DFT) based approach that (i) yields reliable bandgaps, (ii) is free of empirically tuned parameters, and (iii) exhibits low computational overhead. Here we show that for Cu2ZnSnS4 and Cu2ZnGeS4 kesterite photovoltaic materials, all three of these demands are met by the DFT plus Hubbard U technique (DFT+U) with corrective parameters evaluated via minimum-tracking linear response. The predicted bandgaps are found to even marginally outperform those from the self-consistent GW approach. Key to this method's success is the application of Hubbard U corrections to all atomic subspaces that dominate the conduction and valence band edges, as opposed to the conventional approach of correcting 3d and 4f atomic states. Intriguingly, the inclusion of Hund's J corrections via the extended DFT+U+J functional significantly worsens these results. This under performance can be ameliorated through the use of the Burgess-Linscott-O'Regan (BLOR) flat-plane based Hubbard U plus Hund's J functional, with bandgap predictions in close agreement with the conventional DFT+U method. The DFT+U method is also used to predict defect-induced changes to the bandgap and associated formation energies, in 1,728-atom supercells.
format Preprint
id arxiv_https___arxiv_org_abs_2512_14548
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Accurate bandgaps of photovoltaic kesterites from first-principles DFT+U
Burgess, Andrew C.
MacEnulty, Lórien
D'Arcy, Ethan
Gavin, David
O'Regan, David D.
Materials Science
Strongly Correlated Electrons
Chemical Physics
Streamlined prediction of the electronic properties of photoactive materials warrants a Density Functional Theory (DFT) based approach that (i) yields reliable bandgaps, (ii) is free of empirically tuned parameters, and (iii) exhibits low computational overhead. Here we show that for Cu2ZnSnS4 and Cu2ZnGeS4 kesterite photovoltaic materials, all three of these demands are met by the DFT plus Hubbard U technique (DFT+U) with corrective parameters evaluated via minimum-tracking linear response. The predicted bandgaps are found to even marginally outperform those from the self-consistent GW approach. Key to this method's success is the application of Hubbard U corrections to all atomic subspaces that dominate the conduction and valence band edges, as opposed to the conventional approach of correcting 3d and 4f atomic states. Intriguingly, the inclusion of Hund's J corrections via the extended DFT+U+J functional significantly worsens these results. This under performance can be ameliorated through the use of the Burgess-Linscott-O'Regan (BLOR) flat-plane based Hubbard U plus Hund's J functional, with bandgap predictions in close agreement with the conventional DFT+U method. The DFT+U method is also used to predict defect-induced changes to the bandgap and associated formation energies, in 1,728-atom supercells.
title Accurate bandgaps of photovoltaic kesterites from first-principles DFT+U
topic Materials Science
Strongly Correlated Electrons
Chemical Physics
url https://arxiv.org/abs/2512.14548